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JOSEPH' A. MILLER, 0F `PROVIDENCE, RHODE ISLAND. Letters .Patent No.' 73,364, dated January 14, 1868i, I

IMPROVEMENT STEAM-GENERATORS.

TO' ALL WHOM IT MAYCQNCERN: l

Be it knownA that I, JOSEPH A. MILLER, of Providence, in the county of Providence, and State of Rhode Island, have invented a new and usefulvImprovement in Steam-Boilers, of which the following is a full, clear, andexact description, reference being had to the accompanying drawing, forming part of this speciiication, and which represents a sectional elevation of a steam-boiler constructed according to my improvement.

My invention consists in a combination of shields, arrangediwithin theupper water-space of the boiler, with return-water and deposit-pipes or tubes open at both ends, and arranged to extend downwards between partitions or through tubes connecting the crown and lower sheets ofthe fire-box or boxes, and open at both ends for the circulation of water through them and around the return or deposit-pipes; and said invention also consists in the construction ofthe sides of the {ire-box or boxes, of water-tubes open at both ends, andthe om- I bination of the crown and lower sheets ofthe latter in a. close or bracing manner. as distinguished from a mere suspension of tubes closed at their lowervends.

A boiler thus constructed combines strength with economy, a large amount of heating-surface and active circulation ofthe wat-er with a most eectve and enlarged sediment or deposit-collecting surface, the sediment being deposited below the reach of the direct action of the ire.

Referring to the accompanying drawing, A is theouter shell or case of the boiler, containing within its water-space one, two, or more lire-boxes orchambers, B, with their ash-pits, a, and lto which b b are the fire-- bars. The ilues to the smoke-stack may run from the rear of the {ire-boxes, which have or may have their sides made up of vertical tubes, C, arranged one in rear of the other, on each fireplace side, to any desired extent, according to the' length of the boiler, and which connect, so as to form braces, the crown-sheets aand lower sheets d of the fire-boxes. `These tubes are open at both ends, and thus establish communication .vith the waterspace above and below. In some cases, instead of the tubes C, partition or side plates may be used, with .free water-spaces outside of or between them, and opening above and below, as in the case of the tubes, but tubes are preferable as regards strength, andin other respects. Above the lire-boxes, and arranged to extend' over them, within the water-space ofthe boiler, are shields, D, running, itmay be, the length of the boiler, and projecting up to the' usual water-lcvel, or thcreabouts, but separated from each other and from the crown-sheets of the tireboxes by water-spaces ef. .These shields, which may have vertical sides, are bent or inclined to form bottoms, where they serve to direct sediment into collecting or conducting-tubes, E, suspended from or connected with said shields, and projecting or running down between the partition-plates to the sides of the fire-boxes or tubesl l C Vconstituting said sides, with a narrow but froc'water-space, however, surrounding such tubes, and connecting the water-spaces above and below them to promote circulation 'of the water, rapid and economic generation of steam, and contributing to prevent foaming. The shields D, likewise, materially assist in these respects, the water` having an ascending tendency or course, by the action of the fire, up round the sediment-tubes and under and up between'the shields, and afterwards descending through the latter, and down said tubes, carryingsediment along withit to the bottom of the boiler, or 4below the direct action ofthe fire.

y What ishere claimed, and desired to be secured by Letters Patent, Visl i 1. The combination of the tubes C and E with the shields D, crown-sheets c, and lower sheets d, substantially as specified. I

2. The combination of the shields D with. thc sediment-tubes E and outer tubes 0, essentiallyA as herein set forth.

JOSEPH A. MILLER.

Witnesses CHARLES SELDEN, HENRY MARTIN.' 

